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<html lang="zh">
<head>
<meta charset="UTF-8" />
<title>Heading -- Rico的HTML学习</title>
</head>
<body>
<h1>第一级标题</h1>
<h2 lang="en">Second Heading, language is English</h2>
<h3>第三级标题</h3>
<h4>第四级标题</h4>
<h5>第五级标题</h5>
<h6>第六级标题</h6>
</body>
</html>